Rotomolding News:
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Rotomolding is the process of choice for making large, hollow plastic parts. Advantages vs. other processes include design flexibility (large parts with complex shapes), low tooling costs, and low scrap rates. Polyethylene (LLDPE, HDPE, XLPE) is the most widely used plastic for rotomolding. Typical applications include large tanks, toys, containers, recreation (golf carts, kayaks), and fuel tanks. |
| Processing Stability | |
| The high temperatures, long cycle times, and presence of atmospheric oxygen in the rotomolding process necessitates the use of a robust stabilization system in order to provide a broad processing window. The recommended stabilization system is dependent upon factors such as the level of catalyst residues, food contact requirements, and the type of HALS used to provide light stability. Ciba® IRGANOX® B-Blends are typically used. In addition, Ciba® IRGASTAB® FS 302 is a special processing stabilizer that promotes densification of the polymer during molding and enables the production of high impact products after shorter heating times or lower oven temperatures. |  |
1500 ppm IRGANOX® B 215
or
1500 ppm IRGANOX® B 921 | Excellent general food-contact compliant recommendations
for use in rotomolding grades |
1500 ppm IRGANOX® B 1412 | Excellent recommendation for use in rotomolding grades
having low levels of catalyst residues. Provides resistance
to discoloration on exposure to NOx (gas fading or warehouse
discoloration). |
Light Stability
The inherent weatherability of PE resins used for rotomolding is typically described in terms of "UV X" terminology, in which "X" signifies the number of thousand hours required for elongation at break to drop to 50% of its initial value in compression molded test specimens. The most common grades are UV 4 (for toys), UV 8 (for tanks and recreation applications), and UV 15 (for tanks in high UV environments). Hindered amine light stabilizers are used to extend the life of PE in weatherable applications. For parts containing organic pigments, resistance to color fade can often be enhanced by including an ultraviolet absorber such as Ciba® TINUVIN® 326.
| Special Effects | |
| Antistats | |
The use of classical antistats in rotomolding applications can provide benefits such as reduced pigment swirling (when dry color is used), improved mold release, improved powder flow (e.g. more complete emptying of polymer powder from containers and packages), reduced dust buildup on finished goods (during warehouse storage and on the shelf ), and reduction or elimination of surface charges and static buildup. |  |
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For specific recommendations for your application, please contact us..
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